- Metal-free iodine-promoted direct synthesis of unsymmetrical triarylmethanes
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A highly efficient strategy to synthesize completely unsymmetrical triarylmethanes promoted by iodine under metal-free conditions has been successfully developed. Three different aryl groups were introduced into triarylmethanes in a one-pot reaction from inexpensive and readily available salicylaldehydes, arylboronic acids and arenes via o-QM intermediates generated in situ, delivering a wide range of unsymmetrical triarylmethanes bearing various functional groups in good yields with excellent chemoselectivity.
- Gu, Ying-Chun,Huang, Jie,Wu, Run-Shi,Xu, Da-Zhen,Yang, Qi,Yu, Ya-Qin
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p. 5519 - 5525
(2020/04/17)
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- Ferric chloride–catalyzed deoxygenative chlorination of carbonyl compounds: A comparison of chlorodimethylsilane and dichloromethylsilane system
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Deoxygenative chlorination of carbonyl compounds using the HMe2SiCl/FeCl3/EtOAc and HMeSiCl2/FeCl3/EtOAc systems has been systemically investigated. The HMe2SiCl-FeCl3 system showed the advantages of good substrate applicability, mild reaction conditions, simple operation, low cost, and easy availability of raw materials. Also, it provided a simple and efficient synthesis route for carbonyl deoxychlorination via a one-pot method. Using the HMeSiCl2/FeCl3/EtOAc system, the β-methylchalcone derivative could be obtained in good yields in addition to obtaining the chlorinated compound. Finally, two plausible reaction routes were proposed to describe the formation of the chlorinated compound and the β-methylchalcone derivative.
- Xing, Bing-Han,Zhao, Xuan-Xuan,Qin, Yu-Jun,Zhang, Pu,Guo, Zhi-Xin
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p. 667 - 675
(2020/05/22)
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- Visible Light-Catalyzed Benzylic C-H Bond Chlorination by a Combination of Organic Dye (Acr+-Mes) and N-Chlorosuccinimide
-
By combining "N-chlorosuccinimide (NCS)"as the safe chlorine source with "Acr+-Mes"as the photocatalyst, we successfully achieved benzylic C-H bond chlorination under visible light irradiation. Furthermore, benzylic chlorides could be converted to benzylic ethers smoothly in a one-pot manner by adding sodium methoxide. This mild and scalable chlorination method worked effectively for diverse toluene derivatives, especially for electron-deficient substrates. Careful mechanistic studies supported that NCS provided a hydrogen abstractor "N-centered succinimidyl radical,"which was responsible for the cleavage of the benzylic C-H bond, relying on the reducing ability of Acr?-Mes.
- Xiang, Ming,Zhou, Chao,Yang, Xiu-Long,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
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p. 9080 - 9087
(2020/08/14)
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- Design, synthesis, and molecular docking study of new piperazine derivative as potential antimicrobial agents
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Herein, we describe the successful design and synthesis of seventeen new 1,4-diazinanes, compounds commonly known as piperazines. This group of piperazine derivatives (3a-q) were fully characterized by 1H NMR, 13C NMR, FT-IR, and LCMS spectral techniques. The molecular structure of piperazine derivative (3h) was further established by single crystal X-ray diffraction analysis. All reported compounds were evaluated for their antibacterial and antifungal potential against five bacterial (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa) and two fungal strains (Candida albicans and Cryptococcus neoformans). The complete bacterial screening results are provided. As documented, piperazine derivative 3e performed the best against these bacteria. Additionally, data obtained during molecular docking studies are very encouraging with respect to potential utilization of these compounds to help overcome microbe resistance to pharmaceutical drugs, as explicitly noted in this manuscript.
- Patil, Mahadev,Noonikara Poyil, Anurag,Joshi, Shrinivas D.,Patil, Shivaputra A.,Patil, Siddappa A.,Bugarin, Alejandro
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supporting information
(2019/09/06)
-
- Synthesis and evaluation of potent and selective MGL inhibitors as a glaucoma treatment
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Monoacylglycerol lipase (MGL) inhibition provides a potential treatment approach to glaucoma through the regulation of ocular 2-arachidonoylglycerol (2-AG) levels and the activation of CB1 receptors. Herein, we report the discovery of new series of carbamates as highly potent and selective MGL inhibitors. The new inhibitors showed potent nanomolar inhibitory activity against recombinant human and purified rat MGL, were selective (>1000-fold) against serine hydrolases FAAH and ABHD6 and lacked any affinity for the cannabinoid receptors CB1 and CB2. Protein-based 1H NMR experiments indicated that inhibitor 2 rapidly formed a covalent adduct with MGL with a residence time of about 6 h. This interconversion process “intrinsic reversibility” was exploited by modifications of the ligand's size (length and bulkiness) to generate analogs with “tunable’ adduct residence time (τ). Inhibitor 2 was evaluated in a normotensive murine model for assessing intraocular pressure (IOP), which could lead to glaucoma, a major cause of blindness. Inhibitor 2 was found to decrease ocular pressure by ~4.5 mmHg in a sustained manner for at least 12 h after a single ocular application, underscoring the potential for topically-administered MGL inhibitors as a novel therapeutic target for the treatment of glaucoma.
- Alapafuja, Shakiru O.,Malamas, Michael S.,Shukla, Vidyanand,Zvonok, Alexander,Miller, Sally,Daily, Laura,Rajarshi, Girija,Miyabe, Christina Yume,Chandrashekhar, Honrao,Wood, JodiAnne,Tyukhtenko, Sergiy,Straiker, Alex,Makriyannis, Alexandros
-
-
- α-Diimine-Niobium Complex-Catalyzed Deoxychlorination of Benzyl Ethers with Silicon Tetrachloride
-
α-Diimine niobium complexes serve as catalysts for deoxygenation of benzyl ethers by silicon tetrachloride (SiCl4) to cleanly give two equivalents of the corresponding benzyl chlorides, where SiCl4 has the dual function of oxygen scavenger and chloride source with the formation of a silyl ether or silica as the only byproduct. The reaction mechanism has two successive trans-etherification steps that are mediated by the niobium catalyst, first forming one equivalent of benzyl chloride along with the corresponding silyl ether intermediate that undergoes the same reaction pathway to give the second equivalent of benzyl chloride and silyl ether.
- Parker, Bernard F.,Hosoya, Hiromu,Arnold, John,Tsurugi, Hayato,Mashima, Kazushi
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supporting information
p. 12825 - 12831
(2019/10/19)
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- Organocatalytic Chlorination of Alcohols by P(III)/P(V) Redox Cycling
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A catalytic system for the chlorination of alcohols under Appel conditions was developed. Benzotrichloride is used as a cheap and readily available chlorinating agent in combination with trioctylphosphane as the catalyst and phenylsilane as the terminal reductant. The reaction has several advantages over other variants of the Appel reaction, e.g., no additional solvent is required and the phosphane reagent is used only in catalytic amounts. In total, 27 different primary, secondary, and tertiary alkyl chlorides were synthesized in yields up to 95%. Under optimized conditions, it was also possible to convert epoxides and an oxetane to the dichlorinated products.
- Longwitz, Lars,Jopp, Stefan,Werner, Thomas
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p. 7863 - 7870
(2019/06/27)
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- Ruthenium-Catalyzed Reductive Arylation of N-(2-Pyridinyl)amides with Isopropanol and Arylboronate Esters
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A new three-component reductive arylation of amides with stable reactants (iPrOH and arylboronate esters), making use of a 2-pyridinyl (Py) directing group, is described. The N-Py-amide substrates are readily prepared from carboxylic acids and PyNH2, and the resulting N-Py-1-arylalkanamine reaction products are easily transformed into the corresponding chlorides by substitution of the HN-Py group with HCl. The 1-aryl-1-chloroalkane products allow substitution and cross-coupling reactions. Therefore, a general protocol for the transformation of carboxylic acids into a variety of functionalities is obtained. The Py-NH2 by-product can be recycled.
- Ronson, Thomas O.,Renders, Evelien,Van Steijvoort, Ben F.,Wang, Xubin,Wybon, Clarence C. D.,Prokopcová, Hana,Meerpoel, Lieven,Maes, Bert U. W.
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p. 482 - 487
(2019/01/04)
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- Systematic Evaluation of Sulfoxides as Catalysts in Nucleophilic Substitutions of Alcohols
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Herein, a method for the nucleophilic substitution (SN) of benzyl alcohols yielding chloro alkanes is introduced that relies on aromatic sulfoxides as Lewis base catalysts (down to 1.5 mol-%) and benzoyl chloride (BzCl) as reagent. A systematic screening of various sulfoxides and other sulfinyl containing Lewis bases afforded (2-methoxyphenyl)methyl sulfoxide as optimal catalyst. In contrast to reported formamide catalysts, sulfoxides also enable the application of plain acetyl chloride (AcCl) as reagent. In addition, it was demonstrated that weakly electrophilic carboxylic acid chlorides like BzCl promote Pummerer rearrangement of sulfoxides already at room temperature. This side-reaction also provided the explanation, why sulfoxide catalyzed SN-reactions of alcohols do not allow the effective production of aliphatic and electron deficient chloro alkanes. Comparison experiments provided further insight into the reaction mechanism.
- Motsch, Sebastian,Schütz, Christian,Huy, Peter H.
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supporting information
p. 4541 - 4547
(2018/09/13)
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- Manganese-salen catalyzed oxidative benzylic chlorination
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Abstract: Metalloporphyrins are well-known to serve as the model for mimicking reactivities exhibited by cytochrome P450 hydroxylase. Recent developments on selective C–H halogenation using Mn-porphyrins provided the way for understanding the reactivity as well as mechanism of different halogenase enzymes. In this report, we demonstrated a method for benzylic C–H chlorination using easily prepared Mn(salen) complex as the catalyst, which shows a complementary reactivity of Mn-porphyrins. Here, NaOCl has been used as a chlorinating source as well as the oxidant. Efforts towards understanding the mechanism suggested the formation of the high-valent Mn(V)=O species which is believed to be the key intermediate to conduct this transformation. Graphical abstract: SYNOPSIS Mn(salen)-catalyzed selective benzylic chlorination protocol has been developed using aqueous NaOCl solution. Reactions proceeded efficiently at room temperature and displayed good functional group tolerance. The mechanistic investigation demonstrated that Mn (V) = O species is likely to be the key intermediate which is responsible to generate benzylic radical. EPR and ESI-MS studies confirmed the in situ formation of Mn(IV)-species.[Figure not available: see fulltext.].
- Sasmal, Sheuli,Rana, Sujoy,Lahiri, Goutam Kumar,Maiti, Debabrata
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- Continuous-Flow Multistep Synthesis of Cinnarizine, Cyclizine, and a Buclizine Derivative from Bulk Alcohols
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Cinnarizine, cyclizine, buclizine, and meclizine belong to a family of antihistamines that resemble each other in terms of a 1-diphenylmethylpiperazine moiety. We present the development of a four-step continuous process to generate the final antihistamines from bulk alcohols as the starting compounds. HCl is used to synthesize the intermediate chlorides in a short reaction time and excellent yields. This methodology offers an excellent way to synthesize intermediates to be used in drug synthesis. Inline separation allows the collection of pure products and their immediate consumption in the following steps. Overall isolated yields for cinnarizine, cyclizine, and a buclizine derivative are 82, 94, and 87 %, respectively. The total residence time for the four steps is 90 min with a productivity of 2 mmol h-1. The incredible bulk: Bulk alcohols are converted continuously into chlorides using HCl in a microflow. A reaction network that consists of four steps and two inline separations leads to the continuous preparation of cinnarizine, cyclizine, and a buclizine derivative with yields of 82, 94, and 87 %, respectively. The total residence time for the four steps is 90 min with a productivity of 2 mmol h-1.
- Borukhova, Svetlana,Nol, Timothy,Hessel, Volker
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-
- Direct halogenation of alcohols with halosilanes under catalyst- and organic solvent-free reaction conditions
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A chemoselective method for the direct halogenation of different types of alcohols with halosilanes under catalyst- and solvent-free reaction conditions (SFRC) is reported. Various primary, secondary and tertiary benzyl alcohols and tertiary alkyl alcohols were directly transformed to the corresponding benzyl and alkyl halides, respectively, using chlorotrimethylsilane (TMSCl) and bromotrimethylsilane (TMSBr).
- Ajvazi, Njomza,Stavber, Stojan
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supporting information
p. 2430 - 2433
(2016/05/19)
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- A mild method for the replacement of a hydroxyl group by halogen. 1. Scope and chemoselectivity
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α-Chloro-, bromo- and iodoenamines, which are readily prepared from the corresponding isobutyramides have been found to be excellent reagents for the transformation of a wide variety of alcohols or carboxylic acids into the corresponding halides. Yields are high and conditions are very mild thus allowing for the presence of sensitive functional groups. The reagents can be easily tuned allowing therefore the selective monohalogenation of polyhydroxylated molecules. The scope and chemoselectivity of the reactions have been studied and reaction mechanisms have been proposed.
- Munyemana, Fran?ois,George, Isabelle,Devos, Alain,Colens, Alain,Badarau, Eduard,Frisque-Hesbain, Anne-Marie,Loudet, Aurore,Differding, Edmond,Damien, Jean-Marie,Rémion, Jeanine,Van Uytbergen, Jacqueline,Ghosez, Léon
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p. 420 - 430
(2015/12/31)
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- METHOD OF CONVERTING ALCOHOL TO HALIDE
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The present invention relates to a method of converting an alcohol into a corresponding halide. This method comprises reacting the alcohol with an optionally substituted aromatic carboxylic acid halide in presence of an N-substituted formamide to replace a hydroxyl group of the alcohol by a halogen atom. The present invention also relates to a method of converting an alcohol into a corresponding substitution product. The second method comprises: (a) performing the method of the invention of converting an alcohol into the corresponding halide; and (b) reacting the corresponding halide with a nucleophile to convert the halide into the nucleophilic substitution product.
- -
-
Page/Page column 51; 114; 124
(2017/01/02)
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- Synthesis and Anticancer Activity of 1-(1H -Indol-3-yl)-2-(4-diarylmethylpiperazine-1-yl)ethane-1,2-dione Derivatives
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Several new 1-(4-diarylmethylpiperazine-1-yl)-2-(1H-indol-3-yl)ethane-1,2-dione derivatives were synthesized by acylation of 1-diarylmethylpiperazine with 2-(1H-indol-3-yl)-2-oxoacetyl chloride. Their structures were confirmed by 1H NMR, IR, mass spectra, and elemental analysis. These compounds were further evaluated for their anticancer activity, and most of them were found to have moderate-to-potent antiproliferative activities against Hela, A-549, and ECA-109 cancer cell lines in vitro.
- Jiang, Jun-Rong,Xu, Feng,Wu, Han-Gui
-
-
- Synthesis and evaluation of a 2-benzothiazolylphenylmethyl ether class of histamine H4 receptor antagonists
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Synthesis and biological evaluation of a new class of histamine H4receptor ligands, distinct from the previously reported chemotypes, are described. A virtual screening of our corporate compound collection identified a hit with an undesired dual H3R/H4R activity. Chemical exploration led to the discovery of a more potent and selective 2-benzothiazolylphenylmethyl ether lead compound.
- Labeeuw, Olivier,Levoin, Nicolas,Billot, Xavier,Danvy, Denis,Calmels, Thierry,Krief, Stéphane,Ligneau, Xavier,Berrebi-Bertrand, Isabelle,Robert, Philippe,Lecomte, Jeanne-Marie,Schwartz, Jean-Charles,Capet, Marc
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p. 5263 - 5266
(2016/10/30)
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- Stereoselective synthesis of (z)-1-benzhydryl-4-cinnamylpiperazines via the wittig reaction
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A synthetic method of producing (E)- and (Z)-isomers of 1-benzhydryl-4-cinnamylpiperazines in a specific ratio from corresponding benzhydrylpiperazine is described. Of the three compounds synthesized (5a-c), the ratio of E/Z-isomers remained around 15:85. The key intermediates, 1-benzhydryl-4-(2,2-dimethoxyethyl)piperazine derivatives (3a-c), were prepared by nucleophilic substitution reaction of benzhydrylpiperazines (2a-c) with chloroacetaldehyde dimethylacetal in good yield (up to 88%). Hydrolysis of 3a-c gave the corresponding aldehydes 4a-c, which when subjected to the Wittig reaction followed by column purification to afford 1a-c (E-isomers) and 6a-c (Z-isomers) in pure form. The isolated compounds were characterized by NMR and mass spectral analysis. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.] Copyright
- Shivprakash,Reddy, G. Chandrasekara
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supporting information
p. 600 - 609
(2014/01/17)
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- Synthesis and cytotoxicity studies of novel benzhydrylpiperazine carboxamide and thioamide derivatives
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Synthesis and cytotoxic activities of 32 benzhydrylpiperazine derivatives with carboxamide and thioamide moieties were reported. In vitro cytotoxic activities of compounds were screened against hepatocellular (HUH-7), breast (MCF-7) and colorectal (HCT-116) cancer cell lines by sulphorhodamine B assay. In general, 4-chlorobenzhydrylpiperazine derivatives were more cytotoxic than other compounds. In addition, thioamide derivatives (6a-g) have higher growth inhibition than their carboxamide analogs.
- Gurdal, Enise Ece,Durmaz, Irem,Cetin-Atalay, Rengul,Yarim, Mine
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p. 205 - 214
(2014/04/03)
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- Synthesis of 1-benzhydryl piperazine derivatives and evaluation of their ACE inhibition and antimicrobial activities
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This study presents the synthesis of 14 new 1,4-disubstituted piperazine derivatives from allyl bromides of Baylis-Hillman adduct and 4,4-disubstituted benzhydryl piperazines. All the synthesized compounds were further screened for in vitro ACE inhibitor and antimicrobial activities. Among the synthesized piperazine derivatives, compound 12h showed moderate ACE inhibitor activity as compared to the standard, angiotensin-converting enzyme inhibitor (Sigma). The kinetic data (K m, K i and V max values) of enzyme inhibition for compound 12h and ACE inhibitor standard were also determined. Similarly, all compounds were screened against different bacterial strains. Compounds 12a, 12b, 12d, 12h and 12i showed excellent to moderate activity against various tested bacterial strains. Compounds 12b and 12i showed broad spectrum of antibacterial activity against Pseudomonas aeruginosa, Staphylococcus aureus, S. aureus MLS 16, Escherichia coli, Bacillus subtilis and Klebsiella planticola, while compounds 12a, 12d and 12i showed promising activity against P. aeruginosa (MIC value of 8.96 μM), S. aureus (MIC value of 42.2 μM) and S. aureus MLS 16 (MIC value of 81.3 μM), respectively. The remaining compounds showed activity at a concentration of >491 μM.
- Santhoshi, Amlipur,Kumar, Singam Naveen,Sujitha, Pombala,Poornachandra, Yedla,Sadhu, Partha Sarathi,Kumar, C. Ganesh,Rao, Vaidya Jayathirtha
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p. 3207 - 3219
(2014/05/06)
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- Repurposing the antihistamine terfenadine for antimicrobial activity against staphylococcus aureus
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Staphylococcus aureus is a rapidly growing health threat in the U.S., with resistance to several commonly prescribed treatments. A high-throughput screen identified the antihistamine terfenadine to possess, previously unreported, antimicrobial activity against S. aureus and other Gram-positive bacteria. In an effort to repurpose this drug, structure-activity relationship studies yielded 84 terfenadine-based analogues with several modifications providing increased activity versus S. aureus and other bacterial pathogens, including Mycobacterium tuberculosis. Mechanism of action studies revealed these compounds to exert their antibacterial effects, at least in part, through inhibition of the bacterial type II topoisomerases. This scaffold suffers from hERG liabilities which were not remedied through this round of optimization; however, given the overall improvement in activity of the set, terfenadine-based analogues provide a novel structural class of antimicrobial compounds with potential for further characterization as part of the continuing process to meet the current need for new antibiotics.
- Perlmutter, Jessamyn I.,Forbes, Lauren T.,Krysan, Damian J.,Ebsworth-Mojica, Katherine,Colquhoun, Jennifer M.,Wang, Jenna L.,Dunman, Paul M.,Flaherty, Daniel P.
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supporting information
p. 8540 - 8562
(2014/12/11)
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- Selective naked-eye detection of Hg2+ through an efficient turn-on photoinduced electron transfer fluorescent probe and its real applications
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A simple molecular fluorescent probe 5 has been designed and synthesized by appending anthracene and benzhydryl moieties through a piperazine bridge. The probe upon interaction with different metal ions showed high selectivity and sensitivity (2 ppb) for Hg2+ through fluorescence "turn-on" response in HEPES buffer. The significant fluorescence enhancement (~10-fold) is attributable to PET arrest due to complexation with nitrogen atoms of the piperazine unit and Hg2+ in 1:2 stoichiometry, in which a naked-eye sensitive fluorescent blue color of solution changed to a blue-green (switched-on). As a proof of concept, promising prospects for application in environmental and biological sciences 5 have been utilized to detect Hg 2+ sensitively in real samples, on cellulose paper strips, in protein medium (like BSA), and intracellularly in HeLa cells. Moreover, the optical behavior of 5 upon providing different chemical inputs has been utilized to construct individual logic gates and a reusable combinational logic circuit. The combinational circuit (switch ON mode; OR logic gate) is easily resettable to the original position (switch OFF mode; INHIBIT logic gate) by applying reset chemical inputs (OH- and PO43-) with great reproducibility.
- Srivastava, Priyanka,Razi, Syed S.,Ali, Rashid,Gupta, Ramesh C.,Yadav, Suresh S.,Narayan, Gopeshwar,Misra, Arvind
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p. 8693 - 8699
(2014/12/10)
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- Chlorination of benzylic and allylic alcohols with trimethylsilyl chloride enhanced by natural sodium montmorillonite
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A new and practical method for the efficient chlorination of tertiary, secondary, and primary benzylic and allylic alcohols is described. The method is characterized by the formation of hydrogen chloride from trimethylsilyl chloride and trace water, the formation of a carbenium ion through the protonation of an alcohol and subsequent dehydration, and the chlorination of the carbenium ion. During the process, sodium ion-exchanged montmorillonite plays a crucial role in capturing the generated hydrogen chloride, stabilizing the carbenium intermediate as well as promoting the chlorination.
- Tandiary, Michael Andreas,Masui, Yoichi,Onaka, Makoto
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supporting information
p. 2639 - 2643
(2015/01/09)
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- A simple blue fluorescent probe to detect Hg2+ in semiaqueous environment by intramolecular charge transfer mechanism
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An efficient intramolecular charge transfer fluorescent probe bridging benzhydryl moiety and dansyl fluorophore through piperazine unit has been synthesized and characterized. The photophysical behavior of synthesized probe has been analyzed in the presence of different cations in aqueous acetonitrile solution. The probe has shown sensitivity to detect Hg2+ ion selectively over other tested cations at 20 nM level. The probable mode of binding of Hg2+ through the nitrogen and oxygen atoms of piperazine and dansyl has been established by spectral data analysis.
- Srivastava, Priyanka,Ali, Rashid,Razi, Syed S.,Shahid, Mohammad,Patnaik, Satyakam,Misra, Arvind
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supporting information
p. 3688 - 3693
(2013/07/05)
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- Development of small-molecule probes that selectively kill cells induced to express mutant RAS
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Synthetic lethal screening is a chemical biology approach to identify small molecules that selectively kill oncogene-expressing cell lines with the goal of identifying pathways that provide specific targets against cancer cells. We performed a high-throughput screen of 303,282 compounds from the National Institutes of Health-Molecular Libraries Small Molecule Repository (NIH-MLSMR) against immortalized BJ fibroblasts expressing HRASG12V followed by a counterscreen of lethal compounds in a series of isogenic cells lacking the HRASG12V oncogene. This effort led to the identification of two novel molecular probes (PubChem CID 3689413, ML162 and CID 49766530, ML210) with nanomolar potencies and 4-23-fold selectivities, which can potentially be used for identifying oncogene-specific pathways and targets in cancer cells.
- We?wer, Michel,Bittker, Joshua A.,Lewis, Timothy A.,Shimada, Kenichi,Yang, Wan Seok,MacPherson, Lawrence,Dandapani, Sivaraman,Palmer, Michelle,Stockwell, Brent R.,Schreiber, Stuart L.,Munoz, Benito
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supporting information; experimental part
p. 1822 - 1826
(2012/04/04)
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- Treatment of alcohols with tosyl chloride does not always lead to the formation of tosylates
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Treatment of substituted benzyl alcohols with tosyl chloride resulted in the formation of the corresponding chlorides, not the usual tosylates. A series of experiments demonstrated that it was possible to predict whether chlorination or tosylation would occur for substituted benzyl alcohols and pyridine methanols. Treatment of electron withdrawing group-substituted benzyl alcohols with tosyl chloride gave the corresponding chlorides in moderate yields under mild conditions, which provided a simple way to directly prepare chlorides from alcohols.
- Ding, Rui,He, Yong,Wang, Xiao,Xu, Jingli,Chen, Yurong,Feng, Man,Qi, Chuanmin
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experimental part
p. 5665 - 5673
(2011/09/20)
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- Catalytic phosphorus(V)-mediated nucleophilic substitution reactions: Development of a catalytic appel reaction
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Catalytic phosphorus(V)-mediated chlorination and bromination reactions of alcohols have been developed. The new reactions constitute a catalytic version of the classical Appel halogenation reaction. In these new reactions oxalyl chloride is used as a consumable stoichiometric reagent to generate the halophosphonium salts responsible for halogenation from catalytic phosphine oxides. Thus, phosphine oxides have been transformed from stoichiometric waste products into catalysts and a new concept for catalytic phosphorus-based activation and nucleophilic substitution of alcohols has been validated. The present study has focused on a full exploration of the scope and limitations of phosphine oxide catalyzed chlorination reactions as well as the development of the analogous bromination reactions. Further mechanistic studies, including density functional theory calculations on proposed intermediates of the catalytic cycle, are consistent with a catalytic cycle involving halo- and alkoxyphosphonium salts as intermediates.
- Denton, Ross M.,An, Jie,Adeniran, Beatrice,Blake, Alexander J.,Lewis, William,Poulton, Andrew M.
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experimental part
p. 6749 - 6767
(2011/10/02)
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- Practical conversion of chlorosilanes into alkoxysilanes without generating HCl
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Alcohol-free: A versatile, efficient, and practical synthesis of alkoxysilanes without generation of HCl involves the reaction of chlorosilanes with unsymmetrical ethers in the presence of a Lewis acid (see scheme). The reaction proceeds through selective cleavage of C-O bonds and is superior to conventional processes. Industrially feasible reagents are used and only one by-product results. Copyright
- Wakabayashi, Ryutaro,Sugiura, Yasushi,Shibue, Toshimichi,Kuroda, Kazuyuki
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supporting information; experimental part
p. 10708 - 10711
(2011/12/05)
-
- Discovery of benzhydrylpiperazine derivatives as CB1 receptor inverse agonists via privileged structure-based approach
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The present study describes the identification via privileged structure-based approach of the benzhydrylpiperazine moiety as a potential scaffold to develop novel CB1 receptor modulators. Efficient structural optimization of the initial four hit compounds led to a high quality lead series, represented by compound 6c. Compound 6c is a highly potent and selective CB1 receptor inverse agonist that is able to reduce body weight in diet-induced obese Sprague-Dawley rats. The preparation of privileged structure-based library, the progression from hit to lead, the structure-activity relationships in the lead series and in vitro and in vivo activity of compound 6c are discussed.
- Meng, Tao,Wang, Jue,Peng, Hongli,Fang, Guanghua,Li, Min,Xiong, Bing,Xie, Xin,Zhang, Yongliang,Wang, Xin,Shen, Jingkang
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scheme or table
p. 1133 - 1139
(2010/05/02)
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- Structure-activity relationships of diphenylpiperazine N-type calcium channel inhibitors
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A novel series of compounds derived from the previously reported N-type calcium channel blocker NP118809 (1-(4-benzhydrylpiperazin-1-yl)-3,3-diphenylpropan-1-one) is described. Extensive SAR studies resulted in compounds with IC50 values in the range of 10-150 nM and selectivity over the L-type channels up to nearly 1200-fold. Orally administered compounds 5 and 21 exhibited both anti-allodynic and anti-hyperalgesic activity in the spinal nerve ligation model of neuropathic pain.
- Pajouhesh, Hassan,Feng, Zhong-Ping,Ding, Yanbing,Zhang, Lingyun,Pajouhesh, Hossein,Morrison, Jerrie-Lynn,Belardetti, Francesco,Tringham, Elizabeth,Simonson, Eric,Vanderah, Todd W.,Porreca, Frank,Zamponi, Gerald W.,Mitscher, Lester A.,Snutch, Terrance P.
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scheme or table
p. 1378 - 1383
(2010/07/06)
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- Synthesis of novel 1-benzhydryl-4-(3-(piperidin-4-yl)propyl) piperidine sulfonamides as anticonvulsant agents
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A series of novel 1-benzhydryl-4-(3-(piperidin-4-yl)propyl)piperidine sulphonamide derivatives 8(a-j) was synthesized in good yield and met the structural requirements essential for anticonvulsant properties. The structures of the synthesized compounds were confirmed on the basis of their spectral data and elemental analysis. All the compounds were evaluated for their possible anticonvulsant activity by Maximal Electroshock Seizure (MES) test and their neurotoxic effects were determined by rotorod test. Majority of the compounds were active in MES tests. Compounds 8f and 8g have shown a significant and protective effect on seizure, when compared with standard drug phenytoin. Compound 8f and 8g without a fluoro group showed anticonvulsant activity in MES test as compared with compound 8a and 8b with fluoro substituents. From this study, it is quite apparent that there are at least three parameters for the activity of anticonvulsant drugs, that is, a lipophilic domain, a distal hydrophobic center and two-electron donor (-C-N=) system.
- Vinaya,Veeresh,Ananda Kumar,Prasanna,Ranganatha,Benaka Prasad,Patil,Rangappa
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scheme or table
p. 109 - 115
(2011/02/22)
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- Chlorination of various substrates in subcritical carbon tetrachloride
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Various aliphatic hydrocarbons and the side chains of aromatic hydrocarbons were chlorinated in subcritical carbon tetrachloride. Chlorination of aromatic compounds including 1,4-disubstituted benzenes was investigated. Ketones and sulfones were stable under the employed conditions. Sulfoxides were converted into sulfides in a low to modest yields. The coupling adducts between olefins and carbon tetrachloride were obtained from the reactions of olefins.
- Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Horaguchi, Takaaki
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experimental part
p. 2881 - 2888
(2010/06/16)
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- SUBSTITUTED DIBENZHYDRYLPIPERAZINES
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The present invention relates to new dibenzhydrylpiperazine modulators of histamine receptors, pharmaceutical compositions thereof, and methods of use thereof.
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Page/Page column 26
(2009/07/18)
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- Synthesis and in vitro antiproliferative activity of novel 1-benzhydrylpiperazine derivatives against human cancer cell lines
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In order to explore the antiproliferative effect associated with the piperazine framework, several 1-benzhydrylpiperazine derivatives 8(a-d), 9(a-d) and 10(a-h) were synthesized. Variation in the functional group at N-terminal of the piperazine led to three sets of compounds, bearing the sulfonyl, amide and thiourea, respectively. Their chemical structures were confirmed by 1H NMR, LCMS, IR and elemental analysis. The antiproliferative effect of the compounds were evaluated in vitro using the MTT colorimetric method against one normal cell line (NF-103 skin fibroblast cells) and four human cancer cell lines (MCF-7 breast carcinoma cell line, HepG-2 hepatocellular carcinoma cell line, HeLa cervix carcinoma cell line and HT-29 colon carcinoma cell line) for the time period of 24 h. Among the series, four compounds exhibited interesting growth inhibitory effects against all four cell lines.
- Kumar, C.S. Ananda,Prasad, S.B. Benaka,Vinaya,Chandrappa,Thimmegowda,Kumar, Y.C. Sunil,Swarup, Sanjay,Rangappa
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body text
p. 1223 - 1229
(2009/09/30)
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- Suppression of common-ion return by amines: A method to measure rates of fast SN1 reactions
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(Chemical Equation Presented) Rate constants for solvolyses of benzhydryl chlorides, which take place on the 10 ms to minute time scale, have been determined in aqueous acetone and acetonitrile by conductometry, using conventional conductometers as well as stopped-flow techniques. Secondary and tertiary amines were used to suppress ion recombination (common-ion return) thus giving access to the ionization rate constants k1. The observed common-ion rate depressions can be rationalized by the correlation equation for electrophile-nucleophile combinations, log k(20 °C) = s(E + N), where electrophiles (here: carbocations) are characterized by the parameter Eand nucleophiles (here: chloride anions and solvents) are characterized by N and s. 2009 American Chemical Society.
- Streidl, Nicolas,Antipova, Anna,Mayr, Herbert
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supporting information; experimental part
p. 7328 - 7334
(2010/01/16)
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- The aerobic oxidation of alcohols with a ruthenium porphyrin catalyst in organic and fluorinated solvents
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Carbonylruthenium tetrakis(pentafluorophenyl)porphyrin Ru(TPFPP)(CO) was utilized for the aerobic oxidation of alcohols. The in situ activation of the catalyst with mCPBA provided a species capable of catalyzing the oxidation of alcohols with molecular oxygen. The choice of solvent and additive was crucial to obtaining high activity and selectivity. Secondary aromatic alcohols were oxidized in the presence of the ruthenium porphyrin and tetrabutyl ammonium hydroxide in the solvent bromotrichloromethane, enabling high yields to be achieved (up to 99%). Alternatively, alcohols could be oxidized in perfluoro(methyldecalin) with the ruthenium porphyrin at higher temperatures (140 °C) and elevated oxygen pressures (50 psi). The Royal Society of Chemistry.
- Korotchenko, Vasily N.,Severin, Kay,Gagne, Michel R.
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scheme or table
p. 1961 - 1965
(2009/01/31)
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- Chlorination of aliphatic hydrocarbons, aromatic compounds, and olefins in subcritical carbon tetrachloride
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The reactions of various substrates including aliphatic hydrocarbons, aromatic compounds, and olefins were investigated in subcritical carbon tetrachloride. Ketones and sulfones were stable under the employed conditions. The coupling adducts between olefins and carbon tetrachloride were obtained from the reactions of olefins.
- Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Horaguchi, Takaaki
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scheme or table
p. 6419 - 6422
(2009/04/06)
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- Synthesis and crystal structure of 1-benzhydryl-4-methane-sulfonyl- piperazine
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The title compound, 1-benzhydryl-4-methanesulfonyl-piperazine, was synthesized by the nucleophilic substitution of 1-benzhydryl-piperazine with methyl sulfonyl chloride. The product obtained was characterized by spectroscopic techniques, and the structure was investigated by X-ray crystallography. The compound crystallizes in the monoclinic crystal class in the space group P21/c with cell parameters a=9.5820(4) A, b=16.8150(12) A, c=13.5280(8) A, =127.270(5), and V=1734.5(2)A3 for Z=4. The structure reveals that the piperazine ring is in a chair conformation. There is a large discrepancy around the bond angles of the piperazine N atoms. The geometry around the S atom is distorted tetrahedral.
- Naveen,Sridhar,Prasad, J. Shashidhara,Kumar, C. S. Ananda,Prasad, S. B. Benaka,Thimmegowda,Rangappa
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- Synthesis and evaluation of 1-benzhydryl-sulfonyl-piperazine derivatives as inhibitors of MDA-MB-231 human breast cancer cell proliferation
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A series of novel 1-benzhydryl-sulfonyl-piperazine derivatives 7(a-e) were designed by a nucleophilic substitution reaction of 1-benzhydryl-piperazine with various sulfonyl chlorides and characterized by 1H nuclear magnetic resonance (NMR), liquid chromatography mass spectrometry (LC/MS), Fourier-transform infrared (FTIR), and elemental analysis. Our research is focused on identifying synthetically occurring chemotherapeutic substances capable of inhibiting, retarding, or reversing the process of multistage carcinogenesis. The title compounds were evaluated for their efficacy in inhibiting MDA-MB-231 breast cancer cell proliferation. Compound 1-benzhydryl-4-(4-tert-butyl-benzenesulfonyl)-piperazine (7d) showed significant inhibitory activity. Birkhaeuser 2007.
- Ananda Kumar,Nanjunda Swamy,Thimmegowda,Benaka Prasad,Yip, George W.,Rangappa
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p. 179 - 187
(2008/09/17)
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- Diazo preparation via dehydrogenation of hydrazones with "activated" DMSO
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We report that "activated" dimethyl sulfoxide efficiently dehydrogenates hydrazones to the respective diazo species at -78°C. Under optimized conditions, triethylamine hydrochloride is removed quantitatively by vacuum filtration to provide solutions of diazo compounds. Stable diazo species can be isolated in high yield, or alternatively, the direct treatment of these solutions with carboxylic acids provides esters.
- Javed, Muhammad I.,Brewer, Matthias
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p. 1789 - 1792
(2008/02/02)
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- 4-Aminophenyldiphenylphosphinite (APDPP), a new heterogeneous and acid scavenger phosphinite - Conversion of alcohols, trimethylsilyl, and tetrahydropyranyl ethers to alkyl halides with halogens or N-halosuccinimides
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A new heterogeneous phosphinite, 4-aminophenyldiphenylphosphinite (APDPP), is prepared and used for the efficient conversion of alcohols, trimethylsilyl ethers, and tetrahydropyranyl ethers to their corresponding bromides, iodides, and chlorides in the presence of molecular halogens or N-halosuccinimides. The amino group in this phosphinite acts as an acid scavenger and removes the produced acid. A simple filtration easily removes the phosphinate by-product.
- Iranpoor, Nasser,Firouzabadi, Habib,Gholinejad, Mohammad
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p. 1006 - 1012
(2007/10/03)
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- The chemistry of cyclic carbaphosphazenes: The first observation of (R 2PN)(ClCN)2 (R=Cl, Ph) as a reagent for the conversion of alcohols to aldehydes, ketones, and alkyl chlorides
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The oxidation of nine primary and secondary alcohols to the corresponding aldehydes and ketones has been carried out under mild conditions and in good yields using the cyclocarbaphosphazenes (R2PN)(ClCN)2 [R2P = Cl2 P(1), Ph2P(2)] along with dimethylsulfoxide. While both the P-Cl and C-Cl bonds of the carbaphosphazene can in principle bring about the reaction, we observed an increased preference for the C-Cl bonds over the P-Cl bonds in the oxidation of alcohol. Blocking the reactive P site on the heterocyclic ring with the phenyl groups was found to reduce the yields of the oxidized products, while blocking the C- sites with diethylamino groups resulted in no reaction. In addition, along with DMF, the same cyclocarbaphosphazene has been found to be useful for the conversion of alcohols to alkyl chlorides. Copyright Taylor & Francis Group, LLC.
- Behera, Nabakrushna,Mishra, Pradyumna Kumar,Elias, Anil J.
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p. 2445 - 2452
(2007/10/03)
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- Synthesis and insulin-sensitizing activity of (S)-2-ethoxy-3- phenylpropanoic acid derivatives
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A series of (S)-2-ethoxy-3-phenylpropanoic acid derivatives were synthesized and their insulin-sensitizing activities were evaluated in 3T3-L1 cells. Compounds 1b (EC30 = 9.43 × 10-3 μmol/L), 1d (EC30 = 7.45 × 10-3 μmol/L), 1e (EC 30 = 6.22 × 10-3 μmol/L), and 1f (EC30 = 7.76 × 10-3 μmol/L) exhibited more potent insulin-sensitizing activity than rosiglitazone (EC30 = 2.06 × 10-2 μmol/L).
- Cai, Xiao-Hua,Xie, Bing
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p. 1106 - 1109
(2007/10/03)
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- Synthesis and evaluation of methyl 2-methoxycarbonyl-3-phenylpropionate derivatives as a new type of angiotensin converting enzyme inhibitors
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Methyl 2-methoxycarbonyl-3-phenylpropionate derivatives were prepared, and their inhibitory activities for angiotensin converting enzyme (ACE) were evaluated. Compounds 5b (IC50 = 0.0039 μmol/L), 5d (IC 50 = 0.0027 μmol/L), 5e (IC50 = 0.0021 μmol/L), and 5f (IC50 = 0.0052 μmol/L) exhibited more potent ACE inhibitiory activity than the control drug Captopril (IC50 = 0.0075 μmol/L).
- Cai, Xiao-Hua,Xie, Bing,Guo, Hui
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p. 1110 - 1113
(2007/10/03)
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- Kinetics of the solvolyses of benzhydryl derivatives: Basis for the construction of a comprehensive nucleofugality scale
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A series of 21 benzhydrylium ions (diarylmethylium ions) are proposed as reference electrofuges for the development of a general nucleofugality scale, where nucleofugality refers to a combination of leaving group and solvent. A total of 167 solvolysis rate constants of benzhydrylium tosylates, bromides, chlorides, trifluoroacetates, 3,5-dinitrobenzoates, and 4-nitroben-zoates, two-thirds of which have been determined during this work, were subjected to a least-squares fit according to the correlation equation log k 25°C = Sf(Nf + Ef), where s f and Nf are nucleofuge-specific parameters and E f is an electrofuge-specific parameter. Although nucleofuges and electrofuges characterized in this way cover more than 12 orders of magnitude, a single set of the parameters, namely sf, Nf, and E f, is sufficient to calculate the solvolysis rate constants at 25°C with an accuracy of ± 16%. Because sf ≈ 1 for all nucleofuges, that is, leaving group/ solvent combinations, studied so far, qualitative discussions of nucleofugality can be based on Nf.
- Denegri, Bernard,Streiter, Andre,Juric, Sandra,Ofial, Armin R.,Kronja, Olga,Mayr, Herbert
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p. 1648 - 1656
(2007/10/03)
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- Conversion of hydrazones to alkyl chlorides under Swern oxidation conditions
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The unsubstituted hydrazones derived from aromatic ketones and aldehydes were converted in high yield to the corresponding alkyl chlorides under Swern oxidation conditions. In this unusual oxidation/reduction sequence the substrate undergoes a net reduction under the well established Swern oxidation conditions. Unsubstituted hydrazones derived from cyclohexyl ketones returned elimination products.
- Brewer, Matthias
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p. 7731 - 7733
(2007/10/03)
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- Kinetics of the reactions of halide anions with carbocations: Quantitative energy profiles for SN1 reactions
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Rate constants for the reactions of Laser flash photolytically generated benzhydrylium ions (diarylcarbenium ions) with halide ions have been determined in various solvents, including neat and aqueous acetonitrile as well as some alcohols. Substitution of the rate constants into the correlation equation log k = s(N + E) yields the nucleophilicity parameters N for the halide ions in different solvents. Linear correlations with negative slopes are found between the nucleophilicity parameters N for Cl- and Br- in different solvents and the solvent ionizing powers Y of the corresponding solvents. Increasing halide solvation reduces the rates of carbocation/chloride combinations by approximately half as much as it increases the rates of ionizations of benzhydryl chlorides. Comparison of the solvent dependent nucleophilicity parameters N of halide anions and the nucleophilicity parameters N1 for solvents yields a quantitative prediction of common ion rate depression, as demonstrated by the analysis of a variety of literature reported mass-law constants α. Combination of the rate constants for the reactions of benzhydrylium ions with halide ions (k-1) reported in this work with the ionization constants of benzhydryl halides (k1) and the recently reported rate constants for the reactions of benzhydrylium ions with solvents (k2) yields complete quantitative free energy profiles for solvolysis reactions. The applicability of Hammond's postulate for interpreting solvolysis reactions can thus be examined quantitatively.
- Minegishi, Shinya,Loos, Robert,Kobayashi, Shinjiro,Mayr, Herbert
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p. 2641 - 2649
(2007/10/03)
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- Design, synthesis, and structure-activity relationships of pyrazolo[3,4-d]pyrimidines: A novel class of potent enterovirus inhibitors
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A series of pyrazolo[3,4-d]pyrimidines were synthesized and their antiviral activity was evaluated in a plaque reduction assay. It is very interesting that this class of compounds provide remarkable evidence that they are very specific for human enteroviruses, in particular, coxsackieviruses. Some derivatives proved to be highly effective in inhibiting enterovirus replication at nanomolar concentrations. SAR studies revealed that the phenyl group at the N-1 position and the hydrophobic diarylmethyl group at the piperazine largely influenced the in vitro antienteroviral activity of this new class of potent antiviral agents. It was found that the pyrazolo[3,4-d]pyrimidines with a thiophene substituent, such as compounds 20-24, in general exhibited high activity against coxsackievirus B3 (IC50=0.063-0.089μM) and moderate activity against enterovirus 71 (IC50=0.32-0.65μM) with no apparent cytotoxic effect toward RD (rhabdomyosarcoma) cell lines (CC5025μ M).
- Chern, Jyh-Haur,Shia, Kak-Shan,Hsu, Tsu-An,Tai, Chia-Liang,Lee, Chung-Chi,Lee, Yen-Chun,Chang, Chih-Shiang,Tseng, Sung-Nien,Shih, Shin-Ru
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p. 2519 - 2525
(2007/10/03)
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